Switch mechanism



May 20, 1958 A. BAGNAGATTI 2,835,756

SWITCH MECHANISM Filed May 11, 1955 Af ,f

lll/'A 4@ 54 66 Nm @WHW United States Patent ff' l 2,835,756 SWITCHAchille Bagnagatti, Milan, Italy Application May 11, 1955, Serial No.507,707 6 ClamS. (Cl. 20o-48) This invention relates to a device forcut-ott or knife switches in general, provided with a double expansionelectric contact actuated by opposed pressures carried out by alever-rod, or lever-connecting-rod and rod operative chain, and fittedon insulating posts, particularly suitable to embody cut-off switches ofthe two insulating post type, with contacts revolving in opposeddirections, and with controlled drive and shock damping.

A contact device for knife or cut-off switches vand the like isdescribed in the German Patent 531,339. In said device, a movablecross-arm is provided at both ends with axially fitted contacts movablein opposed directions thereon and suitable to be brought into engagementwith their mating contacts by means of toggle connecting-rod systems,which drive is derived from the means by which said cross-arm is swungfrom one to the other of its rest positions. y

This invention relates to an improvement of the above said, alreadyknown contact device.

The device according to the invention, of the type comprising twomovable contacts which can be resiliently engaged with their matingcontacts by means of ya toggle connecting-rod system, is characterizedin that both the Contact and its mating 'contact are provided withopposed stirrupshaped members, which free ends can be engaged oneanother, thereby establishing an operating colinection, while themovable contacts are provided with two spring brushes, controlled by thetoggle connectingrod system to resilicntly engage themselves with thefree endsof stirrup member with which the mating Contact is provided.

It is to be understood that the device according to this invention couldbe provided with a double contact, by having any of stirrup membersassociated with a related spring contact brush, in such a manner thatthe clamping action of same brushes be mutually oset, while a doubleexpansion contact is obtained.

The invention will be hereinafter disclosed in the followingdescription, taken with reference to the accompanying drawing, wherein adevice aecording to the invention, as iitted to a two-arm cut-olf switchis shown, being both description and drawing given only as a notrestrictive example.

In same drawing:

Fig. 1 is a partly sectional elevation of a cut-olf switch in its closedposition.

Figs. 2, 3 and 4, 5 are plan views, also partly in section of Samecut-oit switch in its different positions, and more precisely in theopen position (see Fig. `2); while the movable contacts are beingengaged and the thrust of brushes is oiset (see Fig. 3), and in theiinal step, while the brushes are being expanded in order to close thecontacts (see Fig. 4).

Referring now to said figures, the cut-ofi switeh as shown consists of abase 10, whereon the two rotary supports 1.214 are fitted, being samesupports connected one another by means of the die-rod 15.

The column insulators 162-18, as fitted on the afore stated supports 1214, are provided with heads 2022,

whereon the pins 24'-26 are' mounted.

Said pins co-operate with boxes 28T-30, whereon the tubular arms 32.--34are firmly secured. The toggles 36f38, keyed to above pins, arearticulated by means of the connecting rods itl- 42, with the $35,755Patented May 20, 195.55

2 The stirrups 48-50 are fastened in opposed positions onto the freeends of said tubular arms, thereby forming gutter-shaped contacts, whichengage one another by .means of conical projections i2- 54, as formed onthe inside, mutually engaging surfaces of said stirrups.

rods i4- 46, which are slidingly tted within said tubular -Z arms 32-34.

The opposed ends of rods 44--46 are guided by the brushes 56-58, securedto the ends of arms .i2- 34. The vsprings till-62, threaded on latterrods, are also held within same brushes and push axially said rods inopposed directions.

The resilient brushes 64-66, as tted on the ends of rods li-46, whichproject out of the legs of stirrups dii-55%, are electrically connectedto their .arms 32-34 through flexible leads 68-70.

The closing of cut-oft switch contacts is obtained by having the columninsulators 16-18 swung around their supports 12-14- The arms 32-34 areswung the one against the other, until a mutual engagement of shapedprojections 52-54 on the stirrups iS-56 takes place, thereby stoppingsaid arms. At the end of such a motion, both larms 32-34 are aligned ontheir longitudinal axes, as shown in Fig. 3. The further rotation ofcolumn insulators 16-13 is not more transmitted to the arms 32-34, owingto mutual engagement of the ends of rods 418-50.

However, a further rotation of connecting rod systems 36-46 and 3S-42occurs, under the action of the columns iti-18, whereby the rods id- 46are caused to slide axially the one against the other.

Thus, the brushes 64;--66 are engaged and elastically pressedrespectively against the outside faces of square ends of the stirrups 43and 50. Said stirrups 48-50 are operatively connected to one anotherwhile performing latter motion, whereby a given stiffness is obtained.

As a result of the aforedescribed operations, the electiieal contactsare closed, thereby setting up adouble path for the current, whichallows a remarkable decrease of the masses as itted on the ends of knifesupporting arms, above all in the case of high amperage cut-offswitches. A p Y More precisely, in addition to mutual engagement ofstiups through the projections 52454, two parallelconnected circuits4S-66f5064l are established.

Moreover, an operative connection, practically free from any stress(above all in respect of column insulators 164-18) between the arms44+46 can be obtained while the cut-oit switch is closed, owingparticularly to the provision of stirrups 48-5.0, whereby the insulatorsare relieved from the stressesas caused by the expansion of contactbrushes 64466, which resilient action is braked and offset.

The stability of contacts in their closed Vpositions is obtained bybringing any of the connecting rod systems 36-40-38-.42 in a positionslightly beyond (i. e. by a few degrees) their dead centres.

The cut-off switch can be opened by performing the aforedescribedoperations in a reversed sequence.

As it is to be understood, further applications of the fore disclosedand illustrated device could. be readily found out,` by making suitablechanges thereto. 4

Thus, f. i., in place of two arms 44-'-46 showing like length, two armsof different length,` anywhere directed, would be titted on the device.

The advantages which can be obtained by the device according to thisinvention are as follows:

(a) A mutual and contemporaneously acting pressure of the expansion, atwo contact system is obtained, thus setting up a double path for thecurrent, which results in a substantial decrease of the masses as fittedon the end of knife supporting arms, particularly in the case of highamperage cut-oli switches.

(b) Thethrust of brushes is applied against the back of contact heads,which engage each other owing to the particular shape of their heads byshowing in front their electrical contact faces.

(c) The column insulators are subjected only to negligible contactstresses while, due to the double expansion operative system, any abruptshock between the contacts can be positively prevented.

(d) Electrical continuity between the two heads while the cut-off switchis closed, due to the fact that both expansion operative systems arebrought slightly beyond their dead centres.

(e) No burning of main contacts due to arcing can occur while throwingthe switch closed or open, since the initial contact is never set upthereon.

(f) Manufacture of cut-oil? switches provided with two column insulatorsonly, by saving one column insulator in respect of three insulatortypes, with open cut-od switch, a greater spark gap between the opposedcontacts being obtained, since there is not any intermediate columninsulator.

What I claim is:

1. A switch mechanism comprising, in combination, a base member; a pairof spaced insulating mountings rotatably mounted on said base member andhaving free end portions; a first toggle arm tixedly mounted at one ofthe ends thereof on said free end portion of one of said insulatingmountings and being rotatable therewith between a circuit openingposition and a circuit closing the ends thereof on said free end portionof said other insulating mounting and being rotatable therewith betweena circuit opening and a circuit closing position; at least one contactmounted on the other end of said first toggle arm; at least a secondcontact mounted on the other end of said second toggle arm, saidcontacts engaging one another when said first and second toggle arms arein their circuit closing positions; first switch holding means mountedat said other end of said first toggle member and adapted to be movedinto engagement with said other end of said second toggle arm when saidarms are in their respective circuit closing positions; first resilientmeans for resiliently urging said first switch holding means out ofengagement with said other end of said second toggle arm; a secondswitching holding means mounted at said `other end of said second togglearm and adapted to move into engagement with said other end of saidfirst toggle arm when said arms are in their respective circuit closingpositions; and means for moving said tirst and second position; a secondtoggle arm xedly mounted at one of switch holding means into engagementwith their respective ends of said toggle arms against the action ofsaid resilient means, whenever desired.

2. A switch mechanism comprising, in combination, a base member; a pairof spaced insulating mountings rotatably mounted on said base member; apair of switch arms, each of said switch arms being lixedly mounted onone of said insulating mountings respectively and being rotatabletherewith between circuit opening and circuit closing positions, each ofsaid switch arms having a free end portion, a contact mounted on saidfree end portion and adapted to engage the contact of said other switcharm when said switch arms are in circuit closing position, a switchholding member mounted adjacent said free end portion and being movableinto a switch holding position wherein said switch holding memberengages said other switch arm, and resilient means for normally urgingsaid switch holding member out of its switch holding position; and meansfor moving said switch arms into circuit closing position wherein saidcontacts make electrical contact with one another and said switchholding members are moved into switch holding position against theaction of said resilient means.

3. A switch mechanism comprising, in combination, a base member; a pairof parallel spaced insulating mountings rotatably mounted on said basemember and extending in a direction substantially transverse to saidbase member; a pair of switch arms, each of said switch arms beingtixedly mounted on one of said insulating mountings respectively andbeing rotatable therewith between circuit opening and circuit closingpositions, said switch arms extending substantially transversely to saidinsulating mountings, each of said switch arms having a free endportion, a contact mounted on said free end portion and adapted toengage the contact of said other switch arm when said switch arms are incircuit closing position, a switch holding member mounted adjacent saidfree end portion and being movable into a switch holding positionwherein said switch holding member engages said other switch arm, andresilient means for normally urging said switch holding member out ofits switch holding position; and means for moving said switch arms intocircuit closing position wherein said contacts make electrical contactwith one another and said switch holding members are moved into switchholding position against the action of said resilient means.

4. A switch mechanism comprising, in combination, a base member; a pairof spaced insulating mountings rotatably mounted on said base member; apair of switch arms, each of said switch arms being iixedly mounted onone of said insulating mountings respectively and being rotatabletherewith between circuit opening and circuit closing positions, each ofsaid switch arms having a free end portion, a U-shaped member mounted onsaidfree end portion, a contact mounted on said U-shaped member andadapted to engage the contact of said other switch arm when said switcharms are in circuit closing position, a switch holding member mountedadjacent said free end portion and being movable into a switch holdingposition wherein said switch holding member engages said other switcharm, and resilient means for normally urging said switch holding memberout of its switch holding position; and means for moving said switcharms into circuit closing position wherein said contacts make electricalContact with one another and said switch holding members are moved intoswitch holding position against the action of said resilient means.

5. A switch mechanism comprising, in combination, a base member; a pairof spaced insulating mountings rotatably mounted on said base member; apair of switch arms, each of said switch arms being iixedly mounted onone of said insulating mountings respectively and being rotatabletherewith between circuit opening and circuit closing positions, each ofsaid switch arms having a free end portion, a U-.shaped member mountedon said free end portion, a contact mounted on an inner face of saidU-shaped member and adjacent the open end of said U-shaped member, saidcontact being adapted to engage the contact of said other switch armwhen said switch arms are in circuit closing position, a switch holdingmember mounted adjacent said free end portion and being movable into aswitch holding position wherein said switch holding member engages anouter face of said U-shaped member on said other Aswitch arm, andresilient means for normally urging said switch holding member out ofits switch holding position; and means for moving said switch arms' intocircuit closing position wherein said contacts make electrical contactwith one another and said switch holding members are moved into switchholding position against the action of said resilient means.

6. Apparatus as claimed in claim 2 wherein said switch holding membersare electrically conductive and form a parallel path for electriccurrent liowing through said contacts in said circuit closing position.

References Cited in the le of this patent UNITED STATES PATENTS

